Paper makers&#39; drying felt



Nov. 12, 1963 B. ERIKSSON 3,110,078

PAPER MAKER'S DRYING FELT Filed Aug. 8, 1960 2 Sheets-Sheet 1 4 INVENTOR B/RG-ER ER l/(S SON Nov. 12, 1963 B. ERIKSSON 3,110,078

PAPER MAKER'S DRYING FELT Filed Aug. 8, 1960 2 Sheets-Sheet 2 Fig. 4

iNVENTOR BIRGER ERIK 550 ,v

United States Patent 3d M 078 Patented Nov. 12, 1963 dice 3,119,073 PAPER MAKERS DRYING FELT Birger Eriksson, Haimstad, Sweden, assignor to Nordiska Maskinfilt Aktieholaget, Halrnstad, Sweden, :1 corporation of Sweden Filed Aug. 8, 196%, Ser. No. 48,125 Claims priority, applicat on Sweden Sept. 3, 1959 9 Claims. (Cl. 28-74) The drying felts used in paper making machines which are woven in two or more layers have hitherto been manufactured endless. The mounting of such endless felt in a paper machine is, however, a very time wasting procedure and consequently one has more and more begun to use nonendiess felts which in open state are drawn into the machines and are then joined at their ends in a suitable manner A commonly used method is to provide the two ends of the felt with fasteners comprising rows of cramps, eyes or analogous means which are attached to the end of the felt and fastened by a lace. Such fasteners are exposed to a continuous wear. The fasteners and the lace, particularly if a metallic lace is used, become worn where they touch each other and the linking cylinders and drying cylinders of the paper making machines. T ley are also liable to corrosion under the influence of the moisture, the acids and the rather high temperature met in the paper making machines. Their use often involves the defect that the lace has a tendency to be bent upwards and thereby to deform the felt and weaken the fastening. If, as has been usual, the felts do not in any case have a very long life, these defects are not too serious but they have to be taken seriously into consideration if the felts are manufactured of a fibrous material which gives them a considerably longer life.

According to the invention, a paper makers felt formed of a number of woven layers is spliced to make it endless by tying together warps from the outer layers of the ends to be spliced, i.e. those layers which are to be remote from the paper, so that the knots be above the inner layers which are juxtaposed.

To that end, the wefts are removed from the outer layers and the inner layers are shortened so that the warps in the outer layers overlie and project beyond a transverse marginal portion of the inner layers.

Preferably, the felt is reinforced by the attachment to it of a reinforcing tape to it immediately beyond the point at which the warps are freed. Also, preferably, the splice is reinforced by being coated with a hardenable or self-hardening plastic.

By means of the invention, a splice can be made which ensures that the surface of the felt which comes into contact with the paper remains smooth, the knots being on the outside of the felt. Further, there is practically no thickening at the splice because the knots lie in a kind of recess in the outer surfaces. The absence of any metallic fasteners reduces the rick of undue wear and the joint between the two fasteners is satisfactorily flexible.

An example of the invention will now be described with reference to the accompanying drawings. In drawings:

FIGURE :1 shows diagrammatically a part of a paper making machine from one of its sides;

FIGURE 2 is a plan view of one of the drying felts shown in FIGURE 1 before its mounting in the machine;

FIGURE 3 shows on an enlarged scale a section on the line IllIll in FIGURE 2 through one border of the drying felt;

FIGURE 4 shows on an enlarged scale a plan view of the rear side of the felt during the seaming; and

FIGURE 5 is a vertical section through the joint on the line VV in FIGURE 4.

FIGURE 1 shows the heated cylinders 1 and 2 of the paper making machine round which is passing a paper web 3 in contact with endless drying felts 4, 5 each of which have a paper supporting surface which presses the paper against the cylinders, The felts 4 and 5 also have a non-paper supporting surface which passes over guide and tension rollers 6, '7 and the felts are dried by being passed over drying cylinders 8.

The felts are manufactured in long pieces such as that shown in FIGURE 2 The felt shown here is woven in four layers. In the two outer layers, i.e. those remote from the paper supporting surface 9 of the felt, the wefts are removed so that the warps 11 are freed as shown in FIGURE 3. The two inner layers i.e. those adjacent to the paper supporting surface, are cut off to form a margin ill lying beneath the warps 11. Immediately alongside this margin, a reinforcing tape-l4 is attached to the outer surface 12 of the (felt which has the effect also of making the shoulder 13 formed by the removal of the Wefts in the outer layers more definite. The margin la) is impregnated or sprayed with a hardenable or self-hardening plastic which is resistant to heat and moisture and which protects the margin against fraying. 7

The ends of the drying felt 4 are connected with each other or spliced after the felt has been inserted in the paper making machine. In order to facilitate the splicing, a transverse board 15 of triangular cross section is used as shown in FIGURES 4 and 5. The ends of the felt are attached to the board 15 by means of pins 16 so that the paper surface 9 faces the board and the margin it? at the two ends of the felt are in butt contact with each other. The warp threads 11 are gathered together in bunches 17 of say four threads and are knotted together as shown at 18 in FIGURES 4 and 5, the surplus ends beyond the knots being cut off. The knots 18 are situated in a recess 19 between the shoulders 13, and, consequently, will be exposed to only little wear when they pass over the drying cylinder 8. The knots 18 are preferably reinforced by spraying or coating with a binding medium, preferably a hardenable or self-hardening synthetic resin which is resistant to heat and moisture.

In order that the splicing may be carried out quickly by a number of workers operating simultaneously, the felt may be provided with locating marks 2t), 21, 22 which can be aligned to enable the splicing to be started at any point in the width of the felt.

In the case of a felt having a large number of layers, the reinforcing tape 14 can be dispensed with. As an alternative to the locating marks 29, 21, 22 described above, selected warps can be given distinctive colours.

What I claim is:

1. An endless drying felt for a paper making machine, comprising a plurality of woven layers and having a paper supporting surface and a non-paper supporting surface, the layers on the non-paper supporting surface of the felt being shorter than the layers of the remainder of the felt and the warps of the said non-paper supporting layers extending beyond said non-paper supporting layers and overlying said layers of the remainder of the felt and projecting beyond said layers of the remainder of the felt in their extended condition, the ends of the said layers of the remainder of the felt abutting each other to form a smooth joint on the paper supporting surface and said warps being tied together to join the ends of the felt and holding said ends of the remainder of said layers in abutting relationship.

2. An endless drying felt as claimed in claim 1 in which the said non-paper supporting surface of said felt has a reinforcing tape attached thereto immediately adjacent the ends of the shorter layers of the felt.

3. An endless drying felt as claimed in claim 1 in which said shorter layers of said felt are impregnated with a hardenable binding medium which is resistant to heat and moisture.

4. An endless drying felt as claimed in claim 1 in which the warps of said shorter layers are in bunches of up to four warp threads, said bunches being tied to corresponding opposed bunches.

5. An endless drying felt as claimed in claim 1 in which the ends of the felt have locating marks thereon for accurately aligning the belts for tying them.

6. A method of forming an endless felt for a paper making machine and having a paper supporting surface and a non-paper supporting surface, comprising the steps of removing the wefts from a portion of at least the layer of a length of felt on the non-paper supporting surface to leave only warps, cutting off the remaining layers at both ends of the length of felt so as to leave a length which is less than the length of the portion from which the Wefts have been removed, abutting the ends of the remaining layers to form a smoot joint on the paper supporting surface, and tying the warps on one end to the warps on the other end to hold the said abutting ends in abutting relationship.

7. A method as claimed in claim 6 in which the ends of the felt are temporarily fixed to a board to hold the ends in abutting relationship during the tying step.

8. A method as claimed in claim 7 in which the surfaces of the board form an apex at which the ends of the belt are abutting.

9. A method as claimed in claim 6 and the further step of coating the apex with a hardenable plastic.

References Cited in the file of this patent i l i i t a a 

1. AN ENDLESS DRYING FELT FOR A PAPER MAKING MACHINE, COMPRISING A PLURALITY OF WOVEN LAYERS AND HAVING A PAPER SUPPORTING SURFACE AND A NON-PAPER SUPPORTING SURFACE, THE LAYERS ON THE NON-PAPER SUPPORTING SURFACE OF THE FELT BEING SHORTER THAN THE LAYERS OF THE REMAINDER OF THE FELT AND THE WARPS OF THE SAID NON-PAPER SUPPORTING LAYERS EXTENDING BVEYOND SAID NON-PAPER SUPPORTING LAYERS AND OVERLYING SAID LAYERS OF THE REMAINDER OF THE FELT AND PROJECTING BEYOND SAID LAYERS OF THE REMAINDER 